Environmental pollution in Mongolia: effects across the lifespan

Impact assessment of a raw coal ban on maternal and child health outcomes in Ulaanbaatar: a protocol for an interrupted time series study

INTRODUCTION

Despite a decade of policy actions, Ulaanbaatar's residents continue to be exposed to extreme levels of air pollution, a major public health concern, especially for vulnerable populations such as pregnant women and children. In May 2019, the Mongolian government implemented a raw coal ban (RCB), prohibiting distribution and use of raw coal in households and small businesses in Ulaanbaatar. Here, we present the protocol for an interrupted time series (ITS; a strong quasi-experimental study design for public health interventions) that aims to assess the effectiveness of this coal ban policy on environmental (air quality) and health (maternal and child) outcomes.

METHODS AND ANALYSIS

Routinely collected data on pregnancy and child respiratory health outcomes between 2016 and 2022 in Ulaanbaatar will be collected retrospectively from the four main hospitals providing maternal and/or paediatric care as well as the National Statistics Office. Hospital admissions data for childhood diarrhoea, an unrelated outcome to air pollution exposure, will be collected to control for unknown or unmeasured coinciding events. Retrospective air pollution data will be collected from the district weather stations and the US Embassy. An ITS analysis will be conducted to determine the RCB intervention impact on these outcomes. Prior to the ITS, we have proposed an impact model based on a framework of five key factors, which were identified through literature search and qualitative research to potentially influence the intervention impact assessment.

ETHICS AND DISSEMINATION

Ethical approval has been obtained via the Ministry of Health, Mongolia (No.445) and University of Birmingham (ERN_21-1403). To inform relevant stakeholders of our findings, key results will be disseminated on both (inter)national and population levels through publications, scientific conferences and community briefings. These findings are aimed to provide evidence for decision-making in coal pollution mitigation strategies in Mongolia and similar settings throughout the world.

Winter Air Pollution from Domestic Coal Fired Heating in Ulaanbaatar, Mongolia, Is Strongly Associated with a Major Seasonal Cyclic Decrease in Successful Fecundity

Pollution of the environment is increasing and threatens the health and wellbeing of adults and children around the globe. The impact of air pollution on pulmonary and cardiovascular disease has been well documented, but it also has a deleterious effect on reproductive health. Ulaanbaatar, the capital city of Mongolia, has one of the highest levels of air pollution in the world. During the extreme winters when temperatures routinely fall below -20 °C the level of air pollution can reach 80 times the WHO recommended safe levels. Heating mainly comes from coal, which is burned both in power stations, and in stoves in the traditional Ger housing. We studied the impact of air pollution on conception rates and birth outcomes in Ulaanbaatar using a retrospective analysis of health data collected from the Urguu Maternity hospital in Ulaanbaatar, Mongolia. Daily levels of SO₂, NO₂, PM₁₀, and PM_2.5 were collected from the government Air Quality Monitoring Stations in Ulaanbaatar for the same period as the study. In January, the month of highest pollution, there is a 3.2-fold decrease in conceptions that lead to the successfully delivered infants compared to October. The seasonal variations in conceptions resulting in live births in this study in Ulaanbaatar are shown to be 2.03 ± 0.20 (10-sigma) times greater than those in the Denmark/North America study of Wesselink et al., 2020. The two obvious differences between Ulaanbaatar and Europe/North America are pollution and temperature both of which are extreme in Ulaanbaatar. The extreme low temperature is mitigated by burning coal, which is the main source of domestic heat especially in the ger districts. This drives the level of pollution so the two are inextricably linked. Infants conceived in the months of June-October had the greatest cumulative PM_2.5 pollution exposure over total gestation, yet these were also the pregnancies with the lowest PM_2.5 exposure for the month of conception and three months prior to conception. The delivered-infant conception rate shows a markedly negative association with exposure to PM_2.5 prior to and during the first month of pregnancy. This overall reduction in fecundity of the population of Ulaanbaatar is therefore a preventable health risk. It is of great consequence that the air pollution in Ulaanbaatar affects health over an entire lifespan including reproductive health. This could be remedied with a clean source of heating.

Impact of Seasonal Winter Air Pollution on Health across the Lifespan in Mongolia and Some Putative Solutions

Environmental pollution of the air, water, and soil comprise an increasingly urgent challenge to global health, well-being, and productivity. The impact of environmental pollution arguably has its greatest impact across the lifespan on children, women of childbearing age, and pregnant women and their unborn children, not only because of their vulnerability during development, but also because of their subsequent longevity. Ulaanbaatar, Mongolia, is a highly instructive, perhaps extreme, example of what happens with recent, rapid urbanization. It is the coldest capital city on Earth, where average ambient temperatures routinely fall below -40°C/F between November and February. During the cold winter period, more than 200,000 "Gers" (traditional felt-lined dwellings) in the "Ger district" burn over 600,000 tons of coal for domestic heating (>3 tons each). Thus, outdoor ambient particulate levels frequently exceed 100 times the WHO-recommended safety level for sustained periods of time, and drive the majority of personal particulate matter exposure. Indoor levels of exposure are somewhat lower in this setting because Gers are equipped with chimneys. Major adverse health impacts that we have documented in the Ger districts include the following: respiratory diseases among those between 1 and 59 years of age and cardiac diseases in those over 60; alarming increases in lung cancer rates in females are also beginning to emerge; and fertility and subsequent successful completion of term pregnancy falls by up to half during the winter pollution season, while early fetal death rises by fourfold. However, the World Bank has intervened with a Ger stove replacement project that has progressively reduced winter pollution by about 30% over the past 5 years, and this has been accompanied by an increase in mean term birth weight of up to 100g. Each incremental decrement in air pollution clearly has beneficial effects on pregnancy, which are likely to have the greatest positive health and macroeconomic impact across the lifespan. However, innovative policies and solutions are clearly needed to eliminate coal heating in Gers and thus further reduce the markedly negative health impact of this practice.

Prenatal and early life exposures to ambient air pollution and development

BACKGROUND

Residential proximity to major roadways, and prenatal exposures to particulate matter <2.5 μm (PM_2.5) and ozone (O₃) are linked to poor fetal outcomes but their relationship with childhood development is unclear.

OBJECTIVES

We investigated whether proximity to major roadways, or prenatal and early-life exposures to PM_2.5 and O₃ increase the risk of early developmental delays.

STUDY DESIGN

Prospective cohort.

SETTINGS

New York State excluding New York City.

PARTICIPANTS

4089 singletons and 1016 twins born between 2008 and 2010.

EXPOSURES

Proximity to major roadway was calculated using road network data from the NY Department of Transportation. Concentrations of PM_2.5 and O₃ estimated by the Environmental Protection Agency Downscaler models were spatiotemporally linked to each child's prenatal and early-life addresses incorporating residential history, and locations of maternal work and day-care.

OUTCOMES

Parents reported their children's development at ages 8, 12, 18, 24, 30 and 36 months in five domains using the Ages and Stages Questionnaire. Generalized mixed models estimated the relative risk (RR) and 95% CI for failing any developmental domain per 10 units increase in PM_2.5 and O₃, and for those living <1000 m away from a major roadway compared to those living further. Models adjusted for potential confounders.

RESULTS

Compared to those >1000 m away from a major roadway, those resided 50-100 m [RR: 2.12 (1.00-4.52)] and 100-500 m [RR: 2.07 (1.02-4.22)] away had twice the risk of failing the communication domain. Prenatal exposures to both PM_2.5 and ozone during various pregnancy windows had weak but significant associations with failing any developmental domain with effects ranging from 1.6% to 2.7% for a 10 μg/m³ increase in PM_2.5 and 0.7%-1.7% for a 10 ppb increase in ozone. Average daily postnatal ozone exposure was positively associated with failing the overall screening by 8 months [3.3% (1.1%-5.5%)], 12 months [17.7% (10.4%-25.5%)], and 30 months [7.6%, (1.3%-14.3%)]. Findings were mixed for postnatal PM_2.5 exposures.

CONCLUSIONS

In this prospective cohort study, proximity to major roadway and prenatal/early-life exposures to PM_2.5 and O₃ were associated with developmental delays. While awaiting larger studies with personal air pollution assessment, efforts to minimize air pollution exposures during critical developmental windows may be warranted.

Health assessment of future PM2.5 exposures from indoor, outdoor, and secondhand tobacco smoke concentrations under alternative policy pathways in Ulaanbaatar, Mongolia

INTRODUCTION

Winter air pollution in Ulaanbaatar, Mongolia is among the worst in the world. The health impacts of policy decisions affecting air pollution exposures in Ulaanbaatar were modeled and evaluated under business as usual and two more-strict alternative emissions pathways through 2024. Previous studies have relied on either outdoor or indoor concentrations to assesses the health risks of air pollution, but the burden is really a function of total exposure. This study combined projections of indoor and outdoor concentrations of PM2.5 with population time-activity estimates to develop trajectories of total age-specific PM2.5 exposure for the Ulaanbaatar population. Indoor PM2.5 contributions from secondhand tobacco smoke (SHS) were estimated in order to fill out total exposures, and changes in population and background disease were modeled. The health impacts were derived using integrated exposure-response curves from the Global Burden of Disease Study.

RESULTS

Annual average population-weighted PM2.5 exposures at baseline (2014) were estimated at 59 μg/m3. These were dominated by exposures occurring indoors, influenced considerably by infiltrated outdoor pollution. Under current control policies, exposures increased slightly to 60 μg/m3 by 2024; under moderate emissions reductions and under a switch to clean technologies, exposures were reduced from baseline levels by 45% and 80%, respectively. The moderate improvement pathway decreased per capita annual disability-adjusted life year (DALY) and death burdens by approximately 40%. A switch to clean fuels decreased per capita annual DALY and death burdens by about 85% by 2024 with the relative SHS contribution increasing substantially.

CONCLUSION

This study demonstrates a way to combine estimated changes in total exposure, background disease and population levels, and exposure-response functions to project the health impacts of alternative policy pathways. The resulting burden analysis highlights the need for aggressive action, including the elimination of residential coal burning and the reduction of current smoking rates.

Urbanization and environmental change during the economic transition on the Mongolian Plateau: Hohhot and Ulaanbaatar

Driven by drastic socioeconomic changes in China and Mongolia, urbanization has become one of the most significant driving forces in the transformation of the Mongolian Plateau in the past 30 years. Using Hohhot and Ulaanbaatar as case studies, we developed a holistic approach to examine the socioeconomic and natural driving forces for urbanization and to investigate the impact on the urban environment. We used a multidisciplinary approach and relied on a variety of data sources to assess the changes of the landscape and environment of the two cities. We detected a rapid urbanization in Hohhot and Ulaanbaatar, both in terms of urban population growth and urban land expansion, from 1990 to 2010, with a much faster speed in 2000-2010. The local geo-physical conditions have constrained the spatial direction of expansion. Ulaanbaatar lagged behind Hohhot for about a decade when measured by indicators of urban population and urban land. Both cities have a degraded urban environment and a growing air pollution epidemic. While Hohhot had worse air pollution than Ulaanbaatar in the early 2000s, the gap between the two cities became smaller after 2010. The research presented here highlights the following as key determinants for urbanization and environmental change: (1) the co-evolution of urbanization, economic development, and environmental change; (2) the urbanization of transitional economies driven by the change of the economic structure, i.e., the development by both manufacturing and tertiary sectors and the change in the primary sector; and (3) the recent institutional changes and increased integration with the global economy.

Seasonal ambient air pollution correlates strongly with spontaneous abortion in Mongolia

Background

Air pollution is a major health challenge worldwide and has previously been strongly associated with adverse reproductive health. This study aimed to examine the association between spontaneous abortion and seasonal variation of air pollutants in Ulaanbaatar, Mongolia.

Methods

Monthly average O₃, SO₂, NO₂, CO, PM₁₀ and PM_2.5 levels were measured at Mongolian Government Air Quality Monitoring stations. The medical records of 1219 women admitted to the hospital due to spontaneous abortion between 2009–2011 were examined retrospectively. Fetal deaths per calendar month from January-December, 2011 were counted and correlated with mean monthly levels of various air pollutants by means of regression analysis.

Results

Regression of ambient pollutants against fetal death as a dose–response toxicity curve revealed very strong dose–response correlations for SO₂ r > 0.9 (p < 0.001) while similarly strongly significant correlation coefficients were found for NO₂ (r > 0.8), CO (r > 0.9), PM₁₀ (r > 0.9) and PM_2.5 (r > 0.8), (p < 0.001), indicating a strong correlation between air pollution and decreased fetal wellbeing.

Conclusion

The present study identified alarmingly strong statistical correlations between ambient air pollutants and spontaneous abortion. Further studies need to be done to examine possible correlations between personal exposure to air pollutants and pregnancy loss.